And three



F. HACHMANN.

SPARK PLUG.

APPLICATION FILED JUNE 26. I919.

1 ,35-7,975, Patented Nov. 9, 1920.

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UNITED STATES a AtlT ENT OFFICE.

FREDERICK HACHMANN, OF ST. LOUIS, MISSOURI, ASSIGNOR OF ONE-SIXTEENTH TO CHAUNCEY R. WATSON, ONE- IXTEENTH TO PHILIP E. lvIOODY, AND ONE SIX- TEENTH TO ELIJAH E. FRASER, ALL OF DETROIT, MICHIGAN, AND THREE EIGHTHS TO DAVID M. HU'I'CHINSON, UL FERGUSON, MISSOURI, AND ONE-FOURTH TO HERMAN C. S'IIIFEL, OF ST. LOUIS, MESSOURI.

SPARK-PLUG.

Application filed June 26, 1919.

To all whom it may concerns Be it known that I, FREDERICK HACH- MANN, a citizen of the United States, and resident of the city of St. Louis and State of Missouri, have invented certain new and useful Improvements in Spark-Plugs, of which the following is a specification containing a full, clear, and exact description, references being had to accompanying drawings, forming a part thereof.

This invention relates to spark plugs and has for its primary object a spark plug which is provided with an auxiliary spark gap, so that the electric discharge will be intensified.

A further object is to provide a spark plug having a porcelain insulator which is divided into three parts and a binding nut swivelly secured between two of the porcelain insulators.

In the drawings:

Figure 1. is a vertical section of my complete device.

Fig. 2 an enlarged sectional view of the binding nut and the insulators.

Fig. 3 is a sectional view of one of the insulators.

Fig. 4 is a sectional View of another por tion of the insulator.

Fig. 5 is a side elevation of the binding nut.

In the construction of my device I provide a casing 6, which is of the usual type, having its lower end threaded as indicated by the numeral 7, and its upper end provided with a hexagonal or Wrench-engaging surface 8. The lower end of the casing 6 is provided with a bore 9, in which an aluminum sleeve 10 is secured. This sleeve 10 is provided with an electrode 11. The casing 6 is further provided with a projecting shoulder 12, the shoulder 12 serving as a. rest for the gasket 13, and on this gasket is placed the insulator 1 1. Secured within the insulator 14 is placed the electrode 15, this electrode being securely baked in the insulator. The upper portion of the casing 6 is provided with a bore 16, a portion of which is screw-threaded as indicated by the numeral 17, and within the bore 16 the insulator 14 is inserted. The screw thread portion 17 of the bore 16 receives the pack Specification of Letters Patent.

Patented Nov. 9, 1920.

Serial No. 306,835.

ing nut 18, so that the member 19 of the insulator 20 may be secured and pressed downward toward the insulator 14;.

Between the insulators 14 and 19 I insert the gasket 21, which is composed of heat resisting resilient material and which will prevent any leakage of gas. The insulator il-ll is eonmosel of the sections 15) and 22, the portion 1.) being: provided with conical recesses 23 and :54. these recesses being formed on opposite ends thereof and sep aratcd from each other by means of a pan tition wall 25. This partition wall is provided with an opening 26, through which the primary electrode 27 is inserted. This electrode is provided at one end with a conical or ball-shaped head 28 and on its other end with screw threads 29, over which the securing wrench 30 and the binding nut 31 are screwed. The insulator 22 is provided with a conical projection 32, which fits securely within the recess 24: formed in the insulator 19, and with a mushroom-shaped flange 33, which projects over a portion of the bindin r nut 18. This insulator is pro vidcd on its upper surface with a circular ress 33, in which the insulator washer 34 is placed, this insulating washer surrounding the electrode 27 and is interposed between the nut 30 and the insulator 22, the object of this bein to prevent leakage. The nut 18 is provided on its upper edge with a flange 35, which flange enters the recessed or under-cut portion 36 of the insulator 22.

W'hen it is desired to assemble my device the nut 18 is inserted between the insulators 19 and 22, the electrode 28 then passed through the opening 26 and the opening 37 formed in the insulators, the packing 34 slipped over the electrode and the nut 30 tightened, thus securely holding the insulators l9 and 22 together and at the same time loosely securing the binding nut 18 between the two insulators. With this construction it is possible, by merely removing the nut 18 from the spark plug, to keep that portion of the plug intact. This is not possihle in the structure of present devices, as when a spark plug is constructed with a narrow gap, it is virtually composed of 4 parts, being the binding nut, the casing and two portions of the insulator.

Another advantage of my device is that an ordinary wrench can he used in securing same to a gasolene engine, or in fact a socket wrench may be employed.

It will be observed that the recess 23 in addition to Forming: a receptacle for receiviup; the conical or ball shaped head 28 also arts :e a primary spark chamber when the insulators H and 19 are secured together. It will further be noted that the aluminin'n sleeve 10 has a higher specific heat than the iron or steel shell 7 surrounding it and will attain a higher tenuJerature than said shell and with the consequent tendency to reduce the greasy carbon deposit to a dry powder which uill readily drop oil the spark plug and pass out through the exhaust manifold without fouling the spark plug or short cin euiting it.

lluring fully describ d my inwution, my claim is:

1. A spark plug comprising it casing, an insulator provided with an electrode mount ed in said casing, an aluminum sleeve surrouiti ing the lower and of said insulator and spaced apart therefrom, an electrode secured to said aluminum sleeve, an insulator provided in its upper and lower ends with a recess mounted in said casing and above the first mentioned insulator, a packing nut for securing said insulators together within said casing, a third insulator mounted within the recess formed in the upper end of the second menl ioned insulator and projecting over and arranged to shield the packing nut, an electrode provided with a conical head tlitfilli'l in; through said last mentioned insulators, said eli'aetrode being provided with screw threads on its upper end, a nut for securing: the second and last mentioned insulators together, and a binding nut mounted on the upper end of said electrode;

2. A spark plug provided with an air gap comprising a casing, screw-threaded at its lower end, its upper end being provided with a Wrench engaging surface, a circular bore formed in both ends of the casing, said bores being of dillerent diameter, so as to form a shoulder between them, a counter bore formed in one of the circular bores, an aluminum sleeve located in said counter bore, an electrode secured within the end of said aluminum sleeve, a gasket located on the shoulder, an insulator located on the gasket, an electrode carried by the insulator, a second insulator superimposed on the first mentioned insulator and spaced apart therefrom, a gasket for separating said insulators, a

third insulator secured to the second mentioned insulator, an electrode extending;- through the last mentioned insulators, a binding nut for securing said insulators together, and a packing nut interposed. between the last mentioned insulators, surrounding the same and adapted to be inserts ul within the casing, and means lo rated on his! nientionm l' electrode to establish electrical mnneetion lit-tween it and a suitable source of supply.

3. A spark plug comprising a casing, an upper and lower porcelain insulator mount rd in said casing, the upper insulator being provided with a recess which forms a spark gap chamber between said insulators, a nut mounted in the casing for securing said iusulators together within the casing, an elem trode provided with a conical sparking point mounted in the upper insulator, an electrode mounted in the lower insulator, an aluminum sleeve mounted in the casing and surround i11 ihe lower insulator and spaced apart lllifltfll'Ulll, and a grounded elect-rode carried by the aluminum sleevei l. A spiuik plug comprising a casing, a, lower porcelain insulator mounted in said casing, an upper insulator composed of two sections, one of which is provided in its lower end with a recess forming a spark chamber, a nut for securing the lower insulator and one of the sections of the upper insulalor together, a llai'nge iormed on one oi the sections of the ipper insulator and probe t-"0nd the circumference of said i 2 electrode mounted through both sec lion ol the upper insulator, said electrode living provided with a conical head located the recess Formed in one of the sections of upper insulator, a nut mounted on the electrode for securing both sections of: the upper insulator together, a packing mounted on the electrode between said nut and the upper section of the upper insulator, an electrode mounted in the lower insulator and projecting beyond both ends thereof, an aluminun-t sleeve located in the lower end of the easing and spaced apart and surrounding the lower end of the lower insulator, and a grounded electrode carried by the lower end of the spark plug.

In testimony whereof, I have signed my name to this specification, in presence of two subscribing witnesses.

FREDERICK HAUHMANN.

VVllZHQSSBS W. C. STEIN. 

